Neutron diffraction investigation of the atomic magnetic structure of iron-nickel invars

The concentration and temperature dependences of the cross sections for magnetic small angle scattering of neutrons are studied by neutron diffraction techniques. The results are interpreted on the basis of models involving perturbing centers and magnetic polarization regions. The absence of a long-range antiferromagnetic order the classical Invar is demonstrated. However the coexistence of short-range antiferromagnetic and long-range ferromagnetic orders in the alloys investigated is assumed